Outcomes of 35 dogs with craniomaxillofacial osteosarcoma treated with stereotactic body radiation therapy.

Canine craniomaxillofacial osteosarcoma (OSA) is most commonly treated surgically; however, in cases where surgery is not feasible or non-invasive treatment is desired, stereotactic body radiation therapy (SBRT) may be elected for local tumour control. In this study, we evaluated 35 dogs treated with SBRT. Nine dogs (26%) had calvarial, seven (20%) had mandibular and 19 (54%) had maxillary OSA. Median time to first event (TFE) was 171 days, and overall median survival time (MST) was 232 days. Site-specific MSTs were 144 days for mandible, 236 days for calvarium and 232 days for maxilla (p = .49). Pulmonary metastatic disease was observed in 12/35 (34%) patients and was detected pre-SBRT in six dogs (17%) and post-SBRT in the remaining six dogs (17%). Eighteen adverse events post-SBRT were documented. Per veterinary radiation therapy oncology group criteria, five were acute (14%) and three were late (9%) grade 3 events. Neurological signs in two dogs were suspected to be early-delayed effects. Cause of death was local progression for 22/35 (63%) patients, metastasis for 9/35 (26%) patients and unknown for four. On univariate analysis, administration of chemotherapy was associated with a longer TFE (p = .0163), whereas volume of gross tumour volume was associated with a shorter TFE (p = .023). Administration of chemotherapy and five fractions versus single fraction of SBRT was associated with increased survival time (p = .0021 and .049). Based on these findings, a treatment protocol incorporating chemotherapy and five fractions of SBRT could be considered for dogs with craniomaxillofacial OSA electing SBRT with careful consideration of normal tissues in the field.

Modified hemipelvectomy techniques in dogs and cats appear well tolerated with good functional outcomes.

OBJECTIVE: To describe the clinical characteristics, procedural techniques, complications, and outcomes of dogs and cats undergoing any of the following modified hemipelvectomy techniques: concurrent partial sacrectomy and/or partial vertebrectomy, osseous excision crossing midline, and reconstruction without the use of local musculature. ANIMALS: 23 client-owned animals (20 dogs and 3 cats) that underwent modified hemipelvectomy techniques. Animals that underwent traditional (nonmodified) hemipelvectomy techniques were excluded. PROCEDURES: The medical records of 3 academic institutions were reviewed, and data were recorded and analyzed. RESULTS: Modified hemipelvectomy was performed with partial sacrectomy and/or vertebrectomy in 11 dogs, excision crossing pelvic midline with concurrent limb amputation in 5 dogs and 2 cats, and closure without use of native muscle or mesh in 4 dogs and 1 cat. Surgery was performed for tumor excision in all cases. Excision was reported as complete in 16 of 23, incomplete in 6 of 23, and not recorded in 1 of 23 animals. All animals survived to discharge. Only animals undergoing partial sacrectomy/vertebrectomy (4/11) experienced postoperative mobility concerns. Major intra- or post-operative complications (grades 3 and 4) occurred in 2 dogs that underwent partial sacrectomy/vertebrectomy, and 1 of these animals experienced a complication that resulted in death. The median time to death or last follow-up was 251 days (range, 3 to 1,642). CLINICAL RELEVANCE: The modified hemipelvectomy techniques reported in this cohort were overall well tolerated with good functional outcomes. These findings support the use of these modified hemipelvectomy techniques in dogs and cats, and previous notions regarding tolerable hemipelvectomy procedures should be reconsidered. However, additional studies with larger numbers of patients undergoing modified hemipelvectomy techniques are needed to gain more information.

Grade shifts in recurrent canine soft tissue sarcomas and mast cell tumors.

OBJECTIVE: To determine the incidence of histologic grade shift (alteration of grade relative to the original tumor) in recurrent canine soft tissue sarcoma (STS) and mast cell tumor (MCT), and to determine the level of agreement between blinded pathologist review and original histology interpretation of STS and MCT grades. ANIMALS: 15 dogs with recurrent cutaneous/subcutaneous STS and 5 dogs with recurrent cutaneous MCT. All included dogs underwent excision of both the primary and recurrent tumors and had tumor samples available for review. PROCEDURES: The medical records and histology database from a single institution were reviewed, and data were recorded and analyzed. A single board-certified veterinary pathologist performed blinded evaluation of all excisional tumor samples, including both primary and recurrent disease, and these were evaluated independently and in conjunction with initial pathologic diagnoses. RESULTS: Based on single pathologist review, 7 of 15 (46.7%) dogs with recurrent STS had grade shift characterized by a higher or lower recurrent tumor grade in 4 of 7 and 3 of 7 cases, respectively, and 1 of 5 dogs with recurrent MCT had grade shift characterized by an increased grade of the recurrent tumor. Variability in reported grade between original histology report and pathologist review occurred for 13 of 30 (43.3%) STS excisional biopsy samples and 0 of 10 MCT excisional biopsy samples. CLINICAL RELEVANCE: Grade shift has been reported in multiple tumor types in people and has the potential to alter prognosis and treatment recommendations. This is the first study to document this phenomenon in dogs. Additional large-scale studies are needed to determine factors associated with grade shift as well as prognostic significance of grade shift for recurrent canine STS and MCT.

Configuration of pathologic fractures in dogs with osteosarcoma following stereotactic body radiation therapy: A retrospective analysis.

For some cases of canine appendicular osteosarcoma (OSA), limb-sparing treatment options are often desired, one of which is stereotactic body radiation therapy (SBRT). A major complication of SBRT is fracture of the irradiated bone at the site of treatment. The present study evaluated 127 appendicular OSA sites in 122 dogs treated with SBRT to identify the most common pathologic fracture locations and configurations. A total of 50 tumours experienced a pathologic fracture, and 38 had imaging sufficient to identify fracture configuration. The distal tibia was more likely to develop a fracture than other sites. Multiple types of fracture configuration (transverse, oblique, spiral and comminuted) were observed. The distal radius was significantly more likely to develop a transverse fracture than other sites. Documentation of fracture location and configuration leads to the identification of the forces contributing to fracture occurrence, since each configuration is a result of different forces acting on each affected bone. Such knowledge is imperative for the development of new approaches to diminish the occurrence of pathologic fractures.

Applications of 3-dimensional printing in small-animal surgery: A review of current practices.

Three-dimensional (3D) printing, also called rapid prototyping or additive manufacturing, transforms digital images into 3D printed objects, typically by layering consecutive thin films of material. This technology has become increasingly accessible to the public, prompting applications in veterinary surgery. Three-dimensional prints provide direct visualization of complex 3D structures and also haptic feedback relevant to surgery. The main objective of this review is to report current applications of 3D printing in small-animal surgery, including surgical education, preoperative planning, and treatment of tissue defects. The reported uses of 3D prints, their proposed advantages, and current limitations are discussed considering published evidence. Aspects of the manufacturing process specific to each application are described, along with current practices in veterinary surgery.